I love Wikipedia for those articles. However, as many fundamental science articles, it is hard at the boundary of original work (which is against the rules: htt

I love Wikipedia for those articles. However, as many fundamental science articles, it is hard at the boundary of original work (which is against the rules: https://en.wikipedia.org/wiki/Wikipedia:No_original_research https://en.wikipedia.org/wiki/Wikipedia:No_original_research ). Interestingly, for the front picture of this article, the originality is "avoided" as it originates from https://networkscience.wordpress.com/2012/05/04/taxonomy-of-matrices/ https://networkscience.wordpress.com/2012/05/04/taxonomy-of-... -- a blog, not a well-citable scientific source.